Convertible high chair



FIG. 1 is a perspective view of the convertible high chair showing the design of our invention;

FIG. 2 is a front view thereof;

FIG. 3 is a top plan view thereof;

FIG. 4 is a bottom view thereof;

FIG. 5 is a rear view thereof; and,

FIG. 6 is a left side view thereof.

The right side view is a mirror image of the left side view. 

The ornamental design for a convertible high chair, as shown and described. 